WILLISTON — The Vermont solid waste district that sold compost contaminated with herbicides is suing its insurance carrier to help recover costs stemming from the episode.

The Chittenden Solid Waste District says it had been led to believe its product liability coverage it had obtained through the Vermont League of Cities and Towns would have covered its losses.

The Burlington Free Press reported the league declined to pay, citing a pollution-exclusion clause in the policy.

Last year, the district discovered that some of the compost it sold was laced with herbicides that killed or damaged plants in hundreds of gardens. The district compensated customers and has been implementing measures to prevent the problem from happening again.